1. Technical Field
Embodiments described in this disclosure generally relate to storage area networks. More particularly, the described embodiments relate to methods and apparatus for introducing cascaded intelligent services for data flowing between a host and a storage device.
2. Description of the Related Art
A storage area network (SAN) provides a high-speed special-purpose network that interconnects different data storage devices and associated data hosts on behalf of a larger network of users. Generally, a SAN is used to attach computer storage devices, e.g., disk arrays, tape libraries, and optical jukeboxes, to a host. The SAN operates such that the storage devices appear to each host as being locally attached, i.e., as though the storage devices where physically connected to the host.
In general, a host accesses one or more storage devices so that traffic flows between the host and a storage device via an existing infrastructure of switches, e.g., a fabric of interconnected Fibre Channel switches. Depending on the number of switches, the path taken by different frames sent between the host and the storage device may differ from one another. In some situations, however, it may be useful to provide intelligent services to the data traffic flowing between a particular host and storage device, and it may be preferable to implement such intelligent services on a switch or appliance device that is not in the existing infrastructure or data path that is located between the host and the storage device. For example, switches positioned in a path of a particular host and storage device pair may not have the necessary intelligence, either hardware or software, to implement such a service. Additionally, one may wish to avoid rewiring the infrastructure between a host and storage device pair so as to not incur significant time, increased complexity, or temporary loss of communication. Further, it may be desirable to locate a service in a remote location from the data path between a host and storage device pair.